We've spoken to ex-Goldman MDs, scrutinized a sample of all those who were promoted two years ago, and looked at the firm's established MD pool. This is what you need to know.

1. On average, it will take 12 years and 11 months after graduating before you become a managing director at Goldman Sachs

Based upon a random sample of 20 people from Goldman's 2013 MD pool, it looks like you'll have to work for nearly 13 years after graduating from a first (bachelor's) degree before you get promoted to MD at Goldman.

Naturally, there are some big variations within this. You can see the spread below, by sector and person. The fastest promotions - in fixed income, oil and gas research, trading and principal investments, happened only eight or nine years after graduating. The slowest happened 23 years later. Nor is the speed of promotion sector specific - some people in fixed income markets roles were promoted after eight years, others were promoted after 11 or 15. Naturally, the MD promotes who'd studied an MBA or started out in a totally different sector (one, Joe Femenia, was an ex-US Navy Seal for seven years) had the most post graduation experience after their promotion (Femenia's promotion after 15 years was actually pretty swift given his years in the Navy and two years out for an MBA).

2. The average MD at Goldman Sachs does not have an MBA, a CFA or a PhD

What kind of qualification will get you into the top spot at Goldman?

Based on publicly available data, we looked at the qualifications held by the existing pool of Goldman Sachs MDs. And guess what? Most don't have any industry-related or higher qualifications at all. Having said, that if you're going to get any kind of qualification as a route to an MD promotion, you probably want to get a top MBA. And, there are certainly some Goldman MDs with PhDs - take Afsheen Afshar, an MD in Goldman's data analytics team who was a post-doctoral fellow studying 'neural prostheses' at Stanford until 2010.

3. The people who get promoted to MD at Goldman are bringing in big revenues for the firm

While it is certainly possible to make MD at Goldman when you work in operations (take Darren Hodges, who graduated in 1994 and became a Goldman ops MD in 2007), it's almost certainly easier to get the promotion when you're actually a revenue generator. "Personally, I only got promoted based on revenue," one (recently) ex-MD tells us, speaking on condition of anonymity. "To a large extent, I don't share values with most people in GS and without being at the very top when it comes to revenue, I doubt I would never have been promoted."

4. But they're also 'culture carriers'

Roy Smith, a former Goldman MD and partner turned professor at the Leonard Stern School of Business, says there are around 2,000 MDs at Goldman out of 34,000 employees and they're not all promoted as revenue generators. "They are selected based on the contribution they make to the firm, which includes their contribution to profits, but also client relations, internal cooperation and teamwork, managerial activity and other qualities such as integrity, loyalty etc," says Smith. "They are subject to extensive 360 degree evaluation and checkings with seniors, contemporaries and subordinates. The effort, of course, is to select the best of the eligible year groups."

5. If you work your way up the Goldman hierarchy internally, your progress should look something like this...

What does perfect progression up Goldman's internal hierarchy look like? Try measuring yourself against the career of Maxim Klimov, an MD and partner in Goldman's Special Situations Group.

Maxim graduated (from Cambridge University) in 1999 and joined Goldman as an analyst. Three years later, he left to study an MBA at London Business School. After that two year course, he was back - as an associate. After three years as an associate, he became a VP, and after four years as a VP he was promoted to MD.

That's what advancement in banking looks like.

6. But plenty of Goldman's current MD pool are external hires

Interestingly, however, plenty of the members of Goldman's existing MD pool were hired in externally in the mid-2000s. Since Goldman decided that it's got an excess of senior staff, we suspect that getting hired into the firm as an MD has become harder. The ex-MD we spoke to said there are plenty of frustrated people in Goldman's mid-ranks who will be miffed if their chances of promotion are ruined by an outsider.

"The young talent is having to wait for longer. It takes longer to get promoted, and when you are, you're paid less than you were in the past," he complained.